Graphite crucible



Sept. 4, 1923. 1,466,739 K. NAKAMURA- GRAPHITE CRUCIBLE Filed March 9.1922 K0 Z0 A/AKAMu/M,

Patented Sept. 4 1%23.

entree stares-[ ENT omen K020 NAKAMURinoF royoonA-eun, JAPAN, assrenonmo nrKos'mMAnUrsUn'o KABUSHIKI KAISHA, on ToYonnA-eUN, YAMAGUCHI, JAPAN,A CORPORATION or JAPAN.

GR PHITE Application filed March 9,

To all whom it may concern:

Be it known that Kozo NAKAMURA, a sub ject of the Emperor or" Japan,residing at No. 8371 Hikoshima, l-Iikoshima-mura; Toyoura-gun, YamaguchiPrefecture, Japan, has invented certain new and usefullmprovements in aGraphite Crucible, of which the following is a specification.

This invention relates to graphite crucibles such as are commonly usedin chemical or metallurgical laboratories or crucible furnaces forsmelting various metals. As herea tofore constructed the side walls ofthese crucibles were composed of plane layers 01"- particles of graphiteextending either in a horizontal, vertical or inclined direction,

and the pressure to which the sidewall of these known types of crucibleswas sub jected in the operation of manufacturing the same was not verygreat. While these prior art crucibles are capable otwithstanding hightemperatures, they would frequently crack or split when local and nonuniform.

contraction or expansion in the side walls thereof was caused indischarging of the melted metal or in the charging of new charges intothe crucible. This cracking or splitting occurs parallel to the planelayers of the side walls after the repeated working of the crucible andthis is a great defect of the prior art constructions even though theyhave the property of ordinarily resisting high temperature The object ofthis invention therefore is to providea new and improved construction ofa crucible in which the objectionable cracking and splitting of the sidewalls thereof is overcome. p Y

In the accompanying drawing is shown a crucible constructed inaccordance with my invention and in the figure oi the drawing the ri hthand side of the crucible is shown in elevation, while the left handside is shown in section.

According to my invention the cracking and splitting of the side wallsoithe crucible is eliminated by modifying the structure of a part or thewhole of the side wall by "forming the wall of a plurality of juxtaposed\l shaped layers of graphite.

;the use of the crucible- I cauornnn.

1922. Serial No, 542,230.

i Referring to the drawing A represents the crucible, B'the sidewallthereof and C the plurality of V shaped layers. The crucible shown inthe drawing is preferably formed by piling up flakes of graphite in anouter mold in plane horizontal layers. The center part of thematerial isthen removed substantially; to permit the insertionof an inner moldwhichis constructed to be ex pansible and capable of'having greatpressure applied horizontally thereto in such a way as to move thesections of the inner moldtowards the outer mold The material occupyingthe space between the outer and inner mold is thus" squeezed between theinner mold whenthe inner mold is expanded and as it can not escapeoutwards it is finally bent to torm the V shaped layers shown in sectionat the left hand side in the figure of the drawing. -When the materialis thus compressed any air which may be within the layers of thegraphite is entirely driven off and a compact mass of v shaped layers isprovided along practically the entire side Wall E.

/Vhenthe side wall of the crucible is constructed as heretofore setforth any small cracks WhlCll might be caused by rapid changes oftemperature differences during are prevented from penetrating entirelythrough the crucible because each oi the layers acts as a protectivesheet from cracks extending either from the outside or from the insideof the side walls.

Furthermore, the V shaped layers permit a greater flexibility forexpansion and contractionbecause of heat changes as the form of thelayers allows for expansion and contraction equally in three directions,whereas the usual form of plane layers can only expand or contract inone direction. 7

.Having thus described my invention what I claim as new and desire tosecureby Letv ters Patent is: I 7

A crucible having the side walls thereof constructed of a plurality ofsuperimposed substantially Vshaped layers of graphite.

In testimony whereof ture.

'KOZO NAKALIURA.

he afiixes his sigma.

